I think the processing requirements for handling on-device Siri would destroy battery life.
This actually doesn't seem to be the case. Take a look at Google Translate's offline voice recognition AND translation - it's really amazing, considering it's all happening on your device.
Re:Amazon Echo Dot
by SapphireSun on Friday March 04, 2016 @03:49AM
(#11222710)
I forget where it was, but they published something about training a very small very fast neural network that could fit comfortably in the phone's memory. Tricky tricky. :D
Plus the only way to train these things at scale is to upload the recordings once you have some usage.
Worse for battery life than firing up the radio?
And devices that listen to you 100% of the time is yet another privacy concern... even if they don't send everything to a remote server.
If you have a human assistant who does that job, he also listens 100% of the time.
But he or she is less vulnerable to being automatically hacked by a three letter agency, foreign government, and/or hacker gathering data for identity theft.
The privacy concern _isn't_ necessarily about having something to hide. It's about the consistent hacking of major systems, and exposure of personal data.
It would be nice for voice recognition platforms to start being built in. I know there's training data that's needed, but there's some convenience afforded.